1021-7.6-杨辉三角

#include <stdio.h>
#define N 15
void main(){
	int a[N][N],i,j;
	printf("杨辉三角\n");
	for (i=0;i<N;i++){
		for (j=0;j<N;j++){
			a[i][j]=0;
			a[i][0]=1;
		    a[i][i]=1;
			}
		
		}
		//add
	for (i=2;i<N;i++){
		for (j=1;j<=i-1;j++){
			a[i][j] = a[i-1][j-1]+a[i-1][j];
			}
		}	
		
		//output
	for (i=0;i<N;i++){
		for (j=0;j<N;j++){
			if(a[i][j])
			printf("%-4d",a[i][j]);
		}
		printf("\n");
	}	
	
	
	
	
	}